Sound box



A. A. DENNIS SOUND BOX June 19, 1923. 1,459,5?7

Filed March 20, 1922 2 Sheets-Sheet 1 "'IIII/ 55 (1H 9 me 9 June 19, 1923. 1,459,577

A. A. DENNIS SOUND BOX Filed March 20, 1922 2 Sheets-Sheet 2 Patented June 19, 1923.

warren stares ALFRED A. DENNIS, OF GRAND RAPIDS, IIICHIGAN.

SOUND BOX.

Application filed March 20, 1922. Serial No. 545,304.

To aZZ whom it may concern: I

Be it known that I, ALF ED A. DENNIS, a citizen of the United States of America, residing at Grand Rapids, in the countyof Kent and State of Michigan, have invented certain new and useful Improvements in Sound Boxes; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enand production faults thereof, the present able others skilled in the art to which it appertains to make and use the same.

This invention relates to a sound box for p'honographs, being primarily directed to a novel construction of sound box inwhioh the diaphragm thereof maybe tensioned by application of an adjustable and yielding spring tension thereon, similar to and producing the same desirable results as does the construction shown in myPatent No. 1,393,434, granted October 11, 1921, without the more or less troublesome manufacturing construction being easily and readily manufactured without especially skilled and careful labor. A further object .of theinvention is to make'the sound box also more. or less productive of many of the desirable results coming from the'structure shown in my pending application for patent Ser. No. 456,977, filed June 13, 1921, in so far as an adjustment of the air volume space under the diaphragm is concerned, but without changing the vibratory area of the diaphragm, this remaining the same at all times. -The'invention in fact combines all of the desirable characteristics of my two prior applications, with an elimination of the faults thereof, with theproduction of a structure which is in shape for practical manufacture to produce a soundbox which may be applied to practically all of the common makes of tone arms used in phonographs. i

For an understanding of the invention, reference may be had to the following de scription, taken in connection withthe accompanying drawings, in which,

Fig. 1 is a front elevation of the sound box of my invention in its preferred form.

Fig. 2 is a'rear elevation thereof.

Figs. 3 and 4 are vertical sections through the sound box, but with the parts in different positions in the two views. i

Figs. 5 and 6 are sectionslike that shown in Fig. 8 of two slightly modified forms of structure of the invention.

' Fig. 7 is a perspective view of the mov-' ablymounted ring which. is used in the sound boxes for changing the air volume back. of the diaphragm and for actuating the spring member toward or away from the same.

Fig. 8 is a fragmentary enlarged partial section and front elevation of the sound box, showing features of the interior construction, and

Fig. 9 is a fragmentary vertical section and development taken on the curved line 99, of Fig. 8. l

Like reference characters refer to like parts in the several figures of the drawings.

In construction, a sound box back 1 of circular outline *and having a relatively thin flange 1 extending from the central thicker portion is used, to which flange at its outer edges, an enclosing ring 2 is securely attached by means of screws. The ring 2 is formed with a continuous annular lip 3 between which and the back, two rubber ring gaskets are clamped, receiving between them the edge portions of the diaphragm 6 which 18 thus spaced a short distance fromlthe the ring 2 between its ends and is attached at one end to the diaphragm at' its center, a screw 8 being used, the head of which is located under or back of the diaphragm. A neck 9 is permanently secured to the back 1 for connection of the sound box 'to a tone arm of a phonograph, the back 1 havlng a central openinglO for' the passage of the vibrations given oftfby the diaphragm through the neck to the tone' arm with which it is connected. So far the construction is conventional and well known.

back 1. The usual stylus 7 is mounted on l A ring 11 is mounted in a circular groove cut in the central thicker portion of back 1, concentric with the opening 10. A wire 12 of spring material is secured at its ends to opposite sides of the ring, the wire pasing diametricallyv across the ring. Its-central portion is covered by a short. length of rubber in the form of a sleeve l3,"as shown. v

A curved slot 14c is cut in the bottonrl for the passage of a pin or operating member 15 whlch is connected to ring 11 and extends through the slot so as to be inposition for turn the ring. The distance which, the ring maybe turned is governed by anadjustable stop member 16 of sheet/metal connected by engagement by the fingers of the operator to turned back and forth by against accidental movement by a .received'in spiral slots 19 cut in the outer side of the groove 20 in which ring 11 is seated. These pins and slots 18 and '19 cause the ring 11 to be moved toward or.

away from the diaphragm when the ring is operation of the member 15. In one position the ring lies entirely within thegroove 20 with its side practically flush with the bottom of the sound box, and in another position, as shown in 4, the ring lies .=close'ly adjacent to the diaphragm but is not in contact therewith, the sleeve 1% bearin against the head of the screw 8. The ring is yieldingly held pair of small springs 21 -which are attached at one end to the ring 11, lying in slots 22 therein and bearing with spring pressure against the side of the groove 20.

As thus constructed, the ring maybe readily moved to eitherio'f the positions sho n n 3 .or Fig. .4, in the first position the sound Ibox being in effect a relatively large sound box which is desirable for instrumental selections. When moved to the second position, the diaphragm is left the same size but the effective volume of air under the same is diminished, bein only that within the ring '11, and at the same time the diaphnagm is affected by the pressure of the member 1:3 against the projecting head ofthe screw 8 which is :used .to attach the stylus to the diaphragm. The wire 12 carrying the sleeve is of spring material and yields but theregis an exertion of pressure against the diaphragm through the screw. VV hen thus positioned, the sound box is not only in offeet a smaller box, but the diaphragm is affected so that the tone quality is changed considerably, making the sound box particularly available for vocal selections, The articu'lation, enunciation and tone is clearer and more disti-nctthan with the larger box,

' and "in every way the result is bettered, The

large-r box is better for instrumental selections for the'production of more full and Inellow tones which are not wanted for the vocal selections where the tones should be more sharp and distinct. Practically any variation in range of tones between those produced by the two positions of the ring and the spring carried thereby may be had,

' as the ring may be stopped at any intermediate point between the two extreme positions, as'is evident. The inner side of the back l, or bottom of the sound box is cut with a-gradually depening wide groove forthe :re ep iien ofthe re he the ri g s the pesit e ishewn in Fig. 3. The sam effec may he ha with various vibration ofthe 11 1 111 bar 1%,, replacing the spring wire 12 is stiff and rigid and has its central portion 24: bent into .U-shape, a coiled spring 25 connected thereto projecting toward the center of the diaphragm 6 and having a rubber disk 26 secured at its free end which bears against the head of screw 8 when the ring 11 is moved toward the diaphragm,as is evident. In Fig. 6, the spring 25. ;is ;-seon-red to the diaphragm by the screw 8 and a rubber disk 26 is attached to '12,, the same ieffeot'being secured, there be ing actually ;a mere reversal ,of :parts without change in action. However, the'last structure is not as practical from a manufacturing standpoint owing to the difficulty of attaching the springs to the diaphragms-without the use of great care, this notbeing as necessary in the other forms. g

This invention as outlined ,is useful and practical, is readily manufactured and is subject to adjustment to take Care of vocal or .to the diaphragm may be controlled as desired, the space volume effective to receive the diaphragm vibrations m ay be adjusted, while at the same time, the relative-proportions vof the diaphragm diameter to the length of the stylus from its point of .attachment to the diaphragm to the place where attached to the sound box remains c ns a t, a ve y necessary feature in sound b ons r on The 11 ne er comes g n t the d ph gm, thereby permitting nh egm at al times.

The invention is -.de c s nd is to be consid red s eemprehending all forms of construction coming within their scope.

I claim:

'1. A sound box for phonographs, inc u ing the usual body, diaphragm ImT I-Ilted thereon and stylus connected to the center of the diaphragm, of a spring bar located under the diaphragm and across the center thereof, said bar being supported-at ,both ends, and means for bringing the bar at its central portion into contact engagement with the diaphragm at the point .of connection 0f the stylus thereto.

2. A sound box for phohogra-phs, including the usual body, diaphragm mounted thereon and stylus connected to the center of the diaphragm, .of an elongated bar of spring material of relatively small (cross seco ed unde the di phragm substantially paralleling the s me p ssmg across t cen er thereeitmeans for support-- ng t ar at ethends.,.and means ferimanthe U bend 24 of bar i need th appended I ually moving the bar back and forth toward the diaphragm whereby the bar may be toward or away from the diaphragm to bring the bar at its central portion intocontact with the diaphragm at the point of con nection of the stylus thereto when said means is moved toward the diaphragm.

4:. A sound box for phonographs, including the usual body, diaphragm mounted thereon and stylus connected to the'diaphragm, of a relatively long and small cross section bar of spring material located under the diaphragm and passing under the point of connection of the stylus thereto, means for supporting the bar and means for manually moving said supporting means toward or away from the diaphragm to bring the bar into contact with the diaphragm at the point of connection of the stylus thereto, said supporting means for the bar being at a relatively long distance from the point of stylus connection to the diaphragm whereby the bar is subject to vibration in synchronism with the diaphragm, substantially as described.

5. A sound box for phonographs,including the usual body, diaphragm mounted thereon and stylus connected to the dia phragm of a flexible spring member mounted under the diaphragm, means mounted on the body under the diaphragm for movement toward or away from the diaphragm, means for manually moving said means whereby, the spring member is tensioned against the diaphragm at the point of 0011- nection of the stylus thereto, said movably mounted means comprising a ring having a diameter less than the diameter of the diaphragm, and means to stop movement of the ring toward the diaphragm before it contacts with the diaphragm.

6. A sound box for phonographs, including the usual body, diaphragm mounted thereon and stylus connected to the diaphragm, of a relatively long and flexible bar of spring material located under and paralleling the diaphragm and passing across the point of connection of the stylus thereto, a screw connecting the stylus to the dia phragm and havinga head located against the under side of the diaphragm, means supporting the bar at both ends leaving the intermediate portion free, a rubber member connected to the bar directly under the head of said screw, and means 'for manually operating the bar to bring rubber member into contact with the head of said screw.

In testimony whereof I afiix my signature.

' I ALFRED A. DENNIS. 

